Loans and Leases (Investments in TDRs, Segregated by Risk Rating Exposure) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	$ 249,136	$ 230,414
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	117,633	87,739
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (1) - (6) Pass [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	11,877	13,165
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (7) Special Mention [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	68	84
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (8) Substandard [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	101,825	67,880
Commerial, Commercial Real Estate, Equipment Financing TDR's [Member] | (9) Doubtful [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total recorded investment of TDRs	$ 3,863	$ 6,610